Unusual File Modification by dns.exe
editUnusual File Modification by dns.exe
editIdentifies an unexpected file being modified by dns.exe, the process responsible for Windows DNS Server services, which may indicate activity related to remote code execution or other forms of exploitation.
Rule type: query
Rule indices:
- winlogbeat-*
- logs-endpoint.events.*
Severity: high
Risk score: 73
Runs every: 5 minutes
Searches indices from: now-6m (Date Math format, see also Additional look-back time
)
Maximum alerts per execution: 100
References:
Tags:
- Elastic
- Host
- Windows
- Threat Detection
- Execution
Version: 3 (version history)
Added (Elastic Stack release): 7.10.0
Last modified (Elastic Stack release): 7.11.2
Rule authors: Elastic
Rule license: Elastic License
Investigation guide
editDetection alerts from this rule indicate potential unusual/abnormal file writes
from the DNS Server service process (dns.exe
) after exploitation from
CVE-2020-1350 (SigRed) has occurred. Here are some possible avenues of
investigation:
- Post-exploitation, adversaries may write additional files or payloads to the system as additional discovery/exploitation/persistence mechanisms.
-
Any suspicious or abnormal files written from
dns.exe
should be reviewed and investigated with care.
Rule query
editevent.category:file and process.name:dns.exe and event.type:(creation or deletion or change) and not file.name:dns.log
Threat mapping
editFramework: MITRE ATT&CKTM
-
Tactic:
- Name: Initial Access
- ID: TA0001
- Reference URL: https://attack.mitre.org/tactics/TA0001/
-
Technique:
- Name: External Remote Services
- ID: T1133
- Reference URL: https://attack.mitre.org/techniques/T1133/
Rule version history
edit- Version 3 (7.11.2 release)
-
- Formatting only
- Version 2 (7.11.0 release)
-
-
Updated query, changed from:
event.category:file and process.name:dns.exe and not file.name:dns.log
-